I have admired this build on hobbytalk and took plenty of notes. Excellent handling of all the details and what a great diorama!
Regarding the lighted panels you could always try printing the reverse image on the back this way the light passes through more naturally like a movie theater light-box poster. I only mention this because of what I read on the other forum.
You somehow managed to nail the color of the sedan. Heres a terrible grab from the happy ending.